Woube Yilkal Asfaw, Dibaba Asseged Bogale, Tameru Berhanu, Fite Richard, Nganwa David, Robnett Vinaida, Demisse Amsalu, Habtemariam Tsegaye
College of Veterinary Medicine and Agriculture, Addis Ababa University, P. O. Box 34, Debre Zeit, Ethiopia; College of Veterinary Medicine, Nursing and Allied Health, Tuskegee University, Tuskegee, AL 36088, USA.
College of Veterinary Medicine, Nursing and Allied Health, Tuskegee University, Tuskegee, AL 36088, USA.
Prev Vet Med. 2015 Nov 1;122(1-2):61-9. doi: 10.1016/j.prevetmed.2015.09.013. Epub 2015 Sep 25.
Contagious bovine pleuropneumonia (CBPP) is a highly contagious bacterial disease of cattle caused by Mycoplasma mycoides subspecies mycoides small colony (SC) bovine biotype (MmmSC). It has been eradicated from many countries; however, the disease persists in many parts of Africa and Asia. CBPP is one of the major trade-restricting diseases of cattle in Ethiopia. In this quantitative risk assessment the OIE concept of zoning was adopted to assess the entry of CBPP into an importing country when up to 280,000 live cattle are exported every year from the northwestern proposed disease free zone (DFZ) of Ethiopia. To estimate the level of risk, a six-tiered risk pathway (scenario tree) was developed, evidences collected and equations generated. The probability of occurrence of the hazard at each node was modelled as a probability distribution using Monte Carlo simulation (@RISK software) at 10,000 iterations to account for uncertainty and variability. The uncertainty and variability of data points surrounding the risk estimate were further quantified by sensitivity analysis. In this study a single animal destined for export from the northwestern DFZ of Ethiopia has a CBPP infection probability of 4.76×10(-6) (95% CI=7.25×10(-8) 1.92×10(-5)). The probability that at least one infected animal enters an importing country in one year is 0.53 (90% CI=0.042-0.97). The expected number of CBPP infected animals exported any given year is 1.28 (95% CI=0.021-5.42). According to the risk estimate, an average of 2.73×10(6) animals (90% CI=10,674-5.9×10(6)) must be exported to get the first infected case. By this account it would, on average, take 10.15 years (90% CI=0.24-23.18) for the first infected animal to be included in the consignment. Sensitivity analysis revealed that prevalence and vaccination had the highest impact on the uncertainty and variability of the overall risk.
牛传染性胸膜肺炎（CBPP）是由丝状支原体丝状亚种小菌落（SC）牛生物型（MmmSC）引起的一种牛的高度传染性细菌性疾病。它在许多国家已被根除；然而，该疾病在非洲和亚洲的许多地区仍然存在。CBPP是埃塞俄比亚牛的主要贸易限制疾病之一。在这项定量风险评估中，采用了世界动物卫生组织（OIE）的分区概念，以评估当每年从埃塞俄比亚西北部拟建的无疫区（DFZ）出口多达280,000头活牛时，CBPP进入进口国的情况。为了估计风险水平，制定了一个六层风险路径（情景树），收集了证据并生成了方程式。使用蒙特卡罗模拟（@RISK软件）在10,000次迭代中，将每个节点处危害发生的概率建模为概率分布，以考虑不确定性和变异性。通过敏感性分析进一步量化了围绕风险估计的数据点的不确定性和变异性。在本研究中，一头注定从埃塞俄比亚西北部DFZ出口的单头牛感染CBPP的概率为4.76×10⁻⁶（95%可信区间=7.25×10⁻⁸ - 1.92×10⁻⁵）。一年内至少有一头感染动物进入进口国的概率为0.53（90%可信区间=0.042 - 0.97）。每年出口的CBPP感染动物的预期数量为1.28（95%可信区间=0.021 - 5.42）。根据风险估计，平均必须出口2.73×10⁶头动物（90%可信区间=10,674 - 5.9×10⁶）才能出现第一例感染病例。据此计算，平均需要10.15年（90%可信区间=0.24 - 23.18）才能使第一头感染动物被纳入托运货物中。敏感性分析表明，患病率和疫苗接种对总体风险的不确定性和变异性影响最大。
